Atypical Teratoid/Rhabdoid Tumor of the Lateral Ventricle: A Case Series and Experience with Molecular Subtyping-Guided Immunotherapy.

[BACKGROUND] Atypical teratoid/rhabdoid tumors (AT/RT) are rare, highly aggressive pediatric central nervous system (CNS) malignancies. AT/RT of the lateral ventricle is an exceptionally rare subgroup, with only 11 reported cases. inactivation is the primary molecular feature of AT/RT. Current consensus is to classify AT/RT based on methylation and molecular profiles into the following subgroups: AT/RT-, AT/RT-, AT/RT-, and a potentially distinct -deficient subtype. AT/RT- exhibits high levels of CD8 tumor-infiltrating lymphocytes, indicating immunogenic potential.

[CASE PRESENTATION] We report three pediatric cases presenting with intracranial hypertension and seizures. Diagnosis was confirmed via histopathology and molecular profiling. Interventions included gross total resection, chemotherapy, radiotherapy, and combined immune checkpoint inhibitors (pembrolizumab and ipilimumab). Outcomes varied from rapid progression to 3-year recurrence-free survival. A cohort of 14 pediatric patients with lateral ventricle AT/RT, comprising 3 institutional cases and 11 cases identified from the PubMed database, was evaluated through a narrative synthesis.

[CONCLUSIONS] These advancements highlight the crucial role of molecular subtyping in tailoring personalized treatments, including epigenetic modifiers and immune-based regimens. However, clinical validation is essential to establish standardized protocols. Integrating genomic, epigenetic, and immune microenvironment profiling may enhance risk assessment and treatment precision, ultimately improving survival and quality of life in pediatric patients.